1. Field of the Invention
An object of the present invention is an improved two-band mobile telephone as well as its method of use. The aim of the invention is to propose a device of this kind that can be used with all types of network.
2. Description of the Prior Art
The field of mobile telephony includes networks known as cell networks in which base stations govern geographical cells and use them to set up links between mobile telephones in these cells and other terminals that are fixed or mobile. The exchanges between the mobile telephones and the base stations are organized according to different protocols corresponding to different standards. For example there is the known GSM 900 MHz standard in which the signals exchanged by a mobile telephone with a base station occupy a frequency band of 880 to 915 MHz while the return signals, from the base station to the mobile telephone, are located in the 925 to 960 MHz band. There is also the known DCS 1800 MHz band in which the above frequency bands are respectively 1710 to 1785 MHz and 1805 to 1880 MHz. Other standards govern other bands. In particular, the PCS standard (in the 1900 MHz range) and the UMTS standard (in the 2100 MHz range) can also be envisaged. On the whole, of the different standards, some (ARDIS, AMPS, CDPD, ISM, IS-54, IS-95 and other standards) have frequency bands located around 900 MHz while the other standards (DCS, PCS, DECT, PACS, PHS, etc.) use the band around 1800 MHz and above. The manufacturers of mobile telephones have therefore designed instruments capable of transmitting and receiving messages around the 900 MHz band, around the 1800 MHz band or around the 900 MHz band or the 1800 MHz band. These instruments are called two-band instruments.
Together with this development, testing tools have been developed to test the quality of mobile telephony networks. These testing tools enable the operators who position base stations in a cell to explore the different places of the cell and measure the quality of reception and transmission of the signals from these different places. These testing instruments are, in practice, mobile telephones also provided with a testing software program that takes measurements, at chosen places, of the qualities of the mobile telephony network. These measured qualities represent for example the level of the received signal coming from the base station in each of the ranges of a frequency band as well as, for a beacon frequency range of these base stations, any interference that would be particularly destructive in these places (this would be designed to identify the frequency ranges to be avoided in this cell) as well as, in general, all the qualities of the transmission and processing done in the base station (filtering of frequency ranges, channel encoding, speech encoding, etc.).
Naturally, to test a mobile telephony network emitting in a 900 MHz band, it is necessary to have an appropriate mobile telephone. Similarly, it is necessary to have another adapted mobile telephone to carry out measurements, at the same place in one and the same cell, of the activity of a base station that makes transmission in another band, for example in the DCS 1800 MHz band.
Furthermore, certain operators, in order to augment their ability to connect large numbers of subscribers, have base stations, in the cells, that are themselves two-band base stations. These two-band base stations are capable firstly of engaging in traffic in one band and in the other, and secondly of organizing the traffic so as to prevent saturation in either band. These two-band base stations can thus engage in traffic with a mobile telephone in one band at the same time as they engage in traffic with another mobile station in another band. If necessary, transmission and reception may be located in two different bands for one and the same mobile telephone. To this end, these two-band base stations receive information, from these mobile telephones entering their cell, according to which these mobile telephones are themselves two-band or not two-band devices. Depending on its work load, the base station may then engage in traffic with these two-band mobile telephones in either band so as to avoid traffic saturation. These two-band base stations must also be controlled with two-band telephones.
This means that the operators"" agents who go on the spot to measure the qualities of the network must have three mobile telephones, one for a first band, one for a second band and one for two-band operation. The use of three types of measuring instruments is a costly constraint that is particularly complicated to implement, given the fact that the agents have to perform large numbers of measurements in several places. To this end, in the places in question, they connect the testing mobile telephone to a portable microcomputer and record the results of the measurement tests in the memory of this portable microcomputer. The testing of three networks then means that the instrument connected to the portable microcomputer must be changed. It also entails corresponding operations in the files of this portable microcomputer.
In principle, there is really no solution to this problem given the fact that the network makes its exchanges with the mobile telephone as a function of the type of this mobile telephone and that, consequently, the tests have to be conducted because of the protocol set up between the base station and the mobile telephone, this protocol itself depending on the type of mobile telephone.
However, in the invention, this problem is resolved by providing a two-band mobile telephone with three modes of operation. These modes of operation may be chosen by an operator, for example by pressing keys of the mobile telephone touchpad or through the connection of the mobile telephone to the portable computer by means of the keyboard of this portable computer. The principle of the invention is then as follows.
The mobile telephone is put into service and declares its type to the network. Its type is represented by parameters recorded in the memory of the mobile telephone. Once this declaration is made, or at least once the mobile telephone is powered on, the parameters are changed. Then the mobile telephone is turned off and then put into service again with the new parameters. These new parameters then set up a mode of operation with the base station that corresponds exclusively to one of the following modes: first band, second band, or two-band. The base station then recognizes the mobile telephone (which is a two-band telephone) respectively as a single-band telephone in the first band, a single-band telephone in the second band or a two-band telephone.
It then exchanges connection signals and traffic signals, corresponding to this recognition, with this mobile telephone. These signals are measured by the mobile telephone test program. These signals are automatically stored in the memory of the portable computer.
At the end of these tests, without any need to stop (or power off) the mobile telephone, the disconnection of the mobile telephone is prompted. In this case, the mobile telephone no longer listens to the network and the network no longer recognizes it. The parameters are then changed (before or after disconnection) and the unit is put into service again. This operation then comprises only a reconnection of the mobile telephone to the mobile telephony network. This network then starts a new recognition procedure with this mobile telephone. Thus, the same instrument has informed the network of another mode of operation (according to another band or according to a two-band mode) and a new campaign of measurements can be undertaken. In this case, the results of the measurements are also stored in a memory of the portable computer since the mobile telephone has not been disconnected from it. The method then leads to the desired result namely that the campaign of measurement of the three networks is conducted with a single instrument without manual operation and without physical disconnection of the mobile telephone from the portable microcomputer.
More generally, outside a testing context, a method of this kind enables a mobile telephone to work in either band or in a two-band manner at request. This choice, which is made possible for the user, may for example be exploited to make him choose a mobile telephony operator.
An object of the invention therefore is a two-band type mobile telephone comprising circuits for working in connection with a mobile telephony network on two frequency bands, the telephone comprising a forcing circuit to enforce a mode of operation during connection in order to operate during connection on only one of these bands.
An object of the invention is also a method for the putting into service of a multiband mobile telephone with a mobile telephony network in which:
the mobile telephone is put into service for a first time, wherein
while the mobile telephone is in service during this first putting into service, the working of the mobile telephone is parametrized with second parameters,
the mobile telephone is put out of service, and then
the mobile telephone is put into service a second time with the second parameters.